input输入框只显示下划线input输入框只显示下划线input输入框只显示下划线input输入框只显示下划线inpu

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<style>
			.blank {
				border-bottom: 1px solid black;
				border-left-width: 0;
				border-top-width: 0;
				border-right-width: 0;
			}
 
			.blank:focus {
				border: none;
				border-bottom: 1px solid black !important;
				box-shadow: none;
				outline: none;
			}
 
			.blank:hover {
				border: none;
				border-bottom: 1px solid black !important;
				box-shadow: none;
			}
		</style>
		<input type="text" class="blank">
	</body>
</html>